This invention relates to a streaked pattern collating apparatus. As herein called, a streaked pattern is typically a fingerprint and may be a pattern drawn by a skilled technician after either a faint fingerprint remain or a latent fingerprint.
The streaked pattern collating apparatus comprises a collating unit supplied with an input pattern signal representative of an input streaked pattern having input streaks which are featured by a plurality of input feature points. The collating unit is for carrying out collation between the input streaked pattern and a reference streaked pattern having reference streaks in connection with a predetermined number of reference feature points which feature the reference streaks by reference feature positions and reference streak directions. The collating unit thereby produces a collation coincidence signal and a collation non-coincidence signal when the input streaked pattern coincides with the reference streaked pattern and when the input streaked pattern does not coincide with the reference streaked pattern, respectively. In other words, the collation coincidence and the collation non-coincidence signals represent coincidence and non-coincidence between the input and the reference streaked patterns, respectively.
The collating unit generally comprises a work memory for memorizing the reference feature positions as memorized points and the reference streak directions as memorized directions in correspondence to the reference feature points. Connected to the work memory, a reading section reads from the work memory, as a read-out feature position, one of the memorized positions that corresponds to one of the reference feature points. Simultaneously, the reading section reads from the work memory, as a read-out streak direction, one of the memorized directions that corresponds to the above-mentioned one of the reference feature points.
Connected to the reading section and supplied with the input pattern signal, a confirming section confirms whether or not one of the input feature points is present in a local area defined by the read-out feature position in the input streaked pattern. More specifically, the local area has a rectangular shape defined by the read-out streak direction in the manner which will become clear as the description proceeds. The confirming section thereby produces a presence confirmed signal and a presence non-confirmed signal when the above-mentioned one of the input feature points is present in the local area and when the above-mentioned one of the input feature points is not present in the local area, respectively.
A counting section is connected to the confirming section and has an initial count equal to zero. The counting section counts up the initial count to an increased count whenever the presence confirmed signal is produced. The counting section thereby produces a count signal representative of the increased count.
A count comparing section is connected to the counting section and has a threshold value. The count comparing section compares the increased count with the threshold value. The threshold value is greater than the initial count and is either equal to or less than the predetermined number of the reference feature points. The count comparing section thereby produces first and second compared result signals when the increased count is and is not less than the threshold value, respectively. The second compared result signal is for use as the collation coincidence signal.
Connected to the work memory and the reading, the confirming, and the count comparing sections, a judging section judges, in response to each of the presence non-confirmed signal and the first compared result signal, whether or not all of the memorized positions and all of the memorized directions are already read from the work memory. The judging section thereby produces an end signal and a non-end signal when all of the memorized positions and all of the memorized directions are already read and are not yet read from the work memory, respectively. The end signal is for use as the collation non-coincidence signal.
Responsive to the non-end signal, the reading section reads from the work memory, as the read-out feature position, a different one of the memorized positions that corresponds to a difference one of the reference feature points. Simultaneously, the reading section reads from the work memory, as the read-out streak direction, a different one of the memorized directions that corresponds to the different one of the reference feature points.
The streaked pattern collating apparatus is defective in that it is not possible to carry out the collation at a high speed. This is because the confirming section operates even in a case where the read-out streak direction does not coincide with a local streak direction of a part of the input streaks that is included in the local area.